Solution 1: Create task with worker URLs that are mapped to your servlet

Let ObjectifyFilter inject the Objectify instance. It your responsibility to encode and handle parameters and to secure your URLs.

Solution 2: Create a DeferredTask

Let GAE handle parameters and security for you. Call ObjectifyService.begin() to manually start an Objectify session. Close this session manually when the task finishes. A try-with-resources block handles everything for you.